The present invention relates generally to web printing presses, and in particular to securing a cutting component on a cylinder of a folder in a web printing press.
Web printing presses print a continuous web of material, such as paper. The continuous web then is cut in a cutting unit of a folder so as to form signatures which can then be folded or output. The web is typically cut at the nip formed by a knife cylinder and an anvil cylinder by a blade carried by the knife cylinder in cooperation with a cutting rubber or other assembly carried by the anvil cylinder.
European Patent Application No. EP 1 136 411 A2 (which corresponds to commonly-owned U.S. patent application Ser. No. 09/533,685, which U.S. application is herewith incorporated by reference herein) discloses a folding apparatus having first cutting and anvil cylinders which partially cut a web so as to form first cuts. The partially cut web is guided between transport tapes to second cutting and anvil cylinders, which cut the web between the first cuts so as to form signatures. The transport tapes pass through axially-spaced grooves in the second cutting and anvil cylinders (see FIGS. 6 and 7).
U.S. Pat. No. 5,259,283 describes a crosscutting device for a folder assembly. A cutting groove cylinder includes a groove strip assembly having a cutting groove component and a pressure spring component for absorbing forces generated during the cutting process. The pressure spring component may be a resilient element (see FIGS. 1 and 3), or a brass body biased toward the cutting groove component by a pressure spring (see FIG. 2). The groove strip assembly is tightly enclosed in a groove in the cutting groove cylinder and has the disadvantage that it is not easily removable.
The blade and cutting rubber wear and must be periodically replaced. With typical prior devices, the blade replacement process is often time consuming and difficult, requiring loosening and tightening of bolts, screws, etc. The cutting rubber may be tightly held under compression in an axial groove machined in the anvil cylinder. Heretofore, replacement of the old cutting rubber has required prying the cutting rubber out of the axial groove with a tool, and then simultaneously bending and tapping the new cutting rubber into the axial groove in the anvil cylinder. For the system disclosed in European Patent Application No. EP 1 136 411 A2, it has proven difficult to properly align grooves formed in the cutting rubber with the axially-spaced tape grooves formed in the cylinder body using the bending and tapping method of inserting the cutting rubber. Often the cutting rubber has be removed and realigned, which may result in damage to the cutting rubber.
In some prior systems, the cutting rubber or blade is housed in an assembly which is removable from the cutting or anvil cylinder. The Quick Set Bar™ of EMT International, for example, purports to be a perforation bar which permits a blade carried by the bar to be quickly and easily changed. However, the entire bar, which includes the anvils between which the blade is clamped, must be removed from the cutting cylinder. There is no teaching to remove the blade alone.